Attachment plug receptacle



Dec. 4, 1934. F. E. JOHNSON 1,983,511

ATTACHMENT PLUG RECEPTACLE Filed April 30, 1929 Patented Dec. 4, 1934 UNITED STATES PATENT OFFICE ATTACHMENT PLUG RECEPTACLE Application April 30, 1929, Serial No. 359,215 4v Claims. (Cl. 173-330) vide a receptacle so formed that the receptacle contacts when loosely mounted therein become locked against displacement or removal thereby eliminating any fastening or supporting means.

Another object is to simplify the receptacle construction and thereby reduce the cost of manufacture.

Other objects of the invention will be more specifically set forth and described hereinafter.

My invention contemplates a receptacle provided with contact receiving recesses so formed that when the contacts are pushed therein they become locked against displacement or removal thereby making it unnecessary to provide any other fastening or supporting means for the contacts. In the preferred form of the invention the receptacle is provided with a recess having an interior shoulder and the contact with a reversed spring contact blade adapted after the contact has been pushed into said recess to impinge against said shoulder to lock the contact within said recess and to the receptacle. The advantages of this construction are that all fastening or supporting means for the contacts are eliminated, the receptacle is simplified in 3:; construction and the assembling operation is expedited to a. large and material degree.

In the accompanying drawing illustrating one form of the invention, Figure 1 is a top plan view of a single receptacle constructed in accordance with my invention; Fig. 2 is a side elevation of the same with an attachment plug in separated relation thereto; Fig. 3 is an end elevation of the receptacle; Fig. 4 is a bottom plan view of the receptacle; Fig. 5 is a longitudinal sectional view on line 55 in Fig. 1; Fig. 6 is a transverse sectional view on line 6-6 in Fig. 1 showing in broken lines a tool for removing the contacts from the receptacle; Fig. 7 is a similar view with the jack blades of the attachment plug inserted; Fig. 8 is a view in perspective of one form of contact and Fig. 9 is a view in perspective of a tool suitable for removing the contacts from the receptacle.

Referring to the drawing showing a single receptacle as one embodiment of the invention,

10 designates a one-piece insulating body of porcelain or other suitable insulating material of circular form having a flat annular boss 12 on its outer face which boss is adapted to project through a circular opening in the wall plate or other mounting. Within the boss are two parallel jack-blade slots 14 which open into a pair of recesses or chambers 16 which in turn open out the lower face 18 of the body. The inner wall of each recess is a continuation of the inner wall of its respective jack-blade slot but the recess is of greater width than the slot being expanded in an outward direction from the center axis of the insulating body. Eachv recess opening in the lower face is, however, restricted by a central lateral extension 20 of the insulating body which forms an interior shoulder 22 at the bottom of the recess adjacent the lower ace.

Loosely mounted within each recess is a resilient contact, the two being identical in form and made from spring ribbon material bent to form a base portion 24 and an upstanding reversed V-portion, the free end 26 of which serves as a resilient or spring contact blade. The base is bored to receive loosely a binding screw 28 held thereon by a square nut 30 threaded on the screw (Fig. 8).

Adjacent each recess there is formed in the lower face of the insulating body a recessed shelf 32 for receiving the base of the resilient contact which shelf is provided with a square recess 34 within which fits the square nut 30 and also with an open slot 36 for accommodating the end of the binding screw 28. Lateral or turning movement of the base of the contact on the recessed shelf 32 or of the nut 30 in its recess is prevented by the sides of the recesses. When mounted in the recess or chamber 16, the free end 26 of the contact engages the shoulder 22 at its intersection with the inner or that wall of the recess which is nearer to the center axis of the insulating body and the other arm of the V-shaped portion engages the outer or that wall of the recess 16 which is further from the said center axis so that the contact is locked within the recess. Preferably, the said outer wall is bevelled outwardly adjacent the recess opening in the lower face and that portion of the contact adjacent its base portion is bent to.'hug said bevelled portion when the contact is mounted in position in the insulating body. So long: as the free end 26 of the contact is in engagement-with the. interior shoulder 22 the contact cannot be displaced or forced out of the recess 16 and is locked therein.

For cooperating with the receptacle there is shown a jack plug 38 having jack blades 40 of usual form. The interior shoulders 22 are of such width that when the jack blades are inserted in the slots in the receptacle to engage the contact blades of the contacts those blades are pushed outwardly but still engage the interior shoulders so that when the jack plug is in operative position the contacts are still locked within the recess (Fig. '7). This construction obviates the necessity of providing any means for fastening the contacts to the insulating body and in mounting the contacts in place they are pushed into the recesses to permit the free ends of the contact blades to snap over the shoulders 22 and against the inner wall of the recess there= upon the contacts are locked and cannot be removed from the insulating body without the use of a special tool. Such a tool is shown in Fig. 9 consisting of a fiat bar 44 having one end bent at an angle to its longitudinal axis and this tool is shown in Fig. 6 in broken lines to illustrate the method of removing a contact from the insulating body. The inclined end of the tool is thrust through the jack blade slot down between the contact blade of the contact and the inner wall of the recess thereby disengaging the contact blade from the shoulder 22 to permit the contact to be withdrawn.

In order to secure a good contact between the jack blades and the contact blades of the contact the latter may be provided with bosses 50 adapted to engage holes 52 in the jack blades so that the blades are locked in contact position and require the exertion of a little additional force to separate the jack from the receptacle.

One form of means for supporting the receptacle in an outlet or switch box is shown comprising a strap 56 set in a transverse recess in the bottom face of the insulating body and secured thereto by a central screw 58 countersunk in a bore in the insulating body. The two ends of the strap are bent upwardly and may be provided with end recesses 64 for fastening the same to the outlet box and with threaded holes 60 for attaching a wall plate thereto.

Although the insulating body may be of any suitable form, yet in the circular form shown the body may be cut away at two sides as shown in Fig. 2 to reduce the weight and at the same time to provide underneath shoulder portions 66 which in some mountings may be used for supporting the receptacle where the strap 56 is not employed. The two jack-blade slots 14 may be made of different sizes if desired to secure polarization.

It will be observed that the assembling of the receptacle itself is accomplished merely by inserting the reversed V-shaped portion of each contact into its respective recess and forcing it in until the contact blade snaps out after passing the lateral partition 22 and pressing the base portion down upon its respective shelf. As shown in Fig. 6 the spring tension of the contact blade keeps its free end against the shoulder 22 and the inner wall of the recess and the other arm of the V-shaped portion against the outer wall of the recess so that after the jack-blades are inserted they come into sliding contact with the contact blades of the contacts, press them outwardly into the position shown in Fig. '7 in which position the lugs on the contact blades are locked in the holes in the jack-blades. With this construction, there is no possibility of the contacts becoming loosened or separated from the receptacle and all fastening means are eliminated. The fastening of the supporting strap that it may be applied with equal facility to a' duplex receptacle and in fact may be used with receptacles of various lrinds and shapes and it is to be understood that the invention is not to be limited to the particular form herein shown and described.

What I claim is:

1. An attachment plug receptacle comprising a one-piece insulating body having an interior expanded recess opening out the lower face of said body, said opening being restricted to form an interior shoulder adjacent said lower face, a resilient contact blade comprising a base and a reversed V-portion, said V-portion being mounted in said recess with its free end in engagement with said interior shoulder to lock said contact therein without other fastening means, and a jack-blade slot entering said recess from the outer face of said body in offset relation to said opening in said lower face, said interior shoulder being of a width suflicient to retain the free end of said contact blade in engagement therewith when a jack-blade is inserted in said slot.

2. An attachment plug receptacle comprising a one-piece insulating body having an interior expanded recess opening out the lower face of said body, said opening being restricted to form an interior shoulder adjacent said lower face, a resilient contact blade comprising a base and a reversed V-portion, said V-portion being mounted in said recess with its free end in engagement with said interior shoulder to lock said contact therein without other fastening means, and a jack-blade slot entering said recess from the outer face of said body, said slot being offset in relation to said opening in the lower face of said body.

3. An attachment plug receptacle comprising a one-piece insulating body having an interior expanded recess opening out both the lower and the top faces of said body, each of said openings being restricted to form an interior shoulder adjacent the face of said insulating body in which said opening is located and said openings being offset in relation to each other, and a resilient contact blade comprising a base and a reversed V-portion, said V-portion extending through the opening in the lower face of said insulating body and being mounted in said recess with its free end in engagement with said interior shoulder adjacent said lower face to lock said contact within said recess without other fastening means, the head of said V-portion being in close proximity to and behind the shoulder adjacent said top face so that a jack-blade entering the opening in said top face comes into sliding engagement with the free end of said contact only.

4. An attachment plug receptacle comprising a one-piece insulating body having an interior expanded recess opening out both the lower and the top faces of said body, each of said openings being restricted to form an interior shoulder adjacent the face of said insulating body in which said opening is located and said openings being offset in relation to each other, and a.

resilient contact blade comprising a base seated on the lower face of said body and a reversed V-portion, said V-portion extending through the opening in the lower face of said insulating body and being mounted in said recess with its free end in engagement with said interior shoulder adjacent said lower face to lock said contact 

